A Method of, and Systems for, Establishing a Connection Between a Remote User Equipment, UE, and a Telecommunication Network Via a Relay Capable UE

ABSTRACT

A method of establishing a connection between a remote User Equipment, UE, and a telecommunication network via a relay capable UE, wherein said telecommunication network comprises a core network and an access network, and wherein said connection is established using a Remote Radio Access Bearer between the remote UE, via a relay capable UE, via an access node in the access network, and the core network.

TECHNICAL FIELD

The present invention is generally related to User Equipments, UEs, thatare connected to a telecommunication network via a relay capable UE.More specifically, the invention relates to a method of establishing aconnection between a remote UE and the telecommunication network via arelay capable UE.

BACKGROUND

Telecommunication networks enable User Equipments, UEs, to communicatewith each other via one of a number of access nodes and via one or morecore networks. Typically, the UE's are mobile terminals designed to beused by human users, such as mobile smart phones, tablets, VirtualReality, VR, headsets, or anything alike. The term UE may also refer toequipment designed to be used in a Machine-to-Machine or Internet ofThings context, such as devices, wearables, sensors, actuators, cameras,cars, media devices, or anything alike. The term UE may also refer togenerally stationary communication devices, such as fixed phones,computers, or stationary Internet of Things, IOT, devices, smart metersor anything alike. In the following description the term User Equipmentis used, which is intended to cover any of the above identified usecases. In the context of the present disclosure, a telecommunicationnetwork comprises the access network, for example the evolved UMTSTerrestrial Radio Access, E-UTRAN, access network as well as the corenetwork, for example the Evolved Packet Core, EPC, network. The accessnode is typically the node in the access network to which a UE directlycommunicates, for example the Evolved Node B, the radio base station oranything alike.

The last couple of years, proximity-based services, ProSe, have beenintroduced in the telecommunication network for providing additionalfunctionality for a UE. The features of ProSe include ProSe discoveryand ProSe Direct Communication.

A ProSe capable UE may perform a ProSe discovery to identifyProSe-enabled UEs in its proximity. Direct Communication enables theestablishment of a direct communication connection between ProSe-enabledUEs that are in direct communication range. The ProSe DirectCommunication path could use different radio technologies, for example,E-UTRAN or Wireless Local Area Network, WLAN, or anything alike.

ProSe Direct communication also facilitates the use of a ProSeUE-to-Network relay, which acts as a relay between the access networkand a remote UE. The ProSe UE-to-Network relay entity thus provides thefunctionality to support connectivity to the telecommunication networkfor remote UE's. A UE is considered to be a remote UE for a certainProSe UE-to-Network relay if it has successfully established a directcommunication path to the UE-to-Network relay. A remote UE can belocated within, or outside, the coverage area of the access node.

The ProSe UE-to-Network Relay relays unicast traffic, uplink as well asdownlink, between the Remote UE and the telecommunication network. TheProSe UE-to-Network Relay provides generic functions that can relay anyInternet Protocol, IP, traffic. Here, ProSe Direct Communication is usedbetween Remote UEs and the ProSe UE-to-Network Relays for the unicasttraffic.

One of the drawbacks of the above identified known methods of relayingtraffic by the UE-to-Network relay is that the network is not able todetermine whether traffic is related to the UE-to-Network Relay orrelated to the remote UE using the UE-to-Network Relay for itsconnection to the telecommunication network.

SUMMARY

It is an objective to provide for methods of establishing a connectionbetween a remote User Equipment, UE, and a telecommunication network viaa relay capable UE.

It is another objective to provide for systems for supportingestablishment of a connection between a remote User Equipment, UE, and atelecommunication network via a relay capable UE.

In a first aspect, there is provided a method of establishing aconnection between a remote User Equipment, UE, and a telecommunicationnetwork via a relay capable UE, wherein said telecommunication networkcomprises a core network and an access network, said access networkcomprising an access node, wherein said relay capable UE has anestablished Radio Access Bearer between said relay capable UE and saidcore network wherein said established Radio Access Bearer comprises:

-   -   a first UE-to-access node bearer between said relay capable UE        and said access node, and    -   an access node-to-core network bearer between said access node        and said core network;    -   said method comprising the steps of:    -   receiving a Request Relay message, from said relay capable UE,        wherein said Request Relay message comprises a request,        originating from said remote UE, for using said relay capable UE        as a relay to the core network, wherein said request is        associated with establishment of a Remote Radio Access Bearer,        wherein said Remote Radio Access Bearer comprises:        -   a UE-to-UE bearer between said remote UE and said relay            capable UE;        -   a second UE-to-access node bearer between said relay capable            UE and said access node, wherein said second UE-to-access            node bearer is different from said first UE-to-access node            bearer, and        -   an access node-to-core network bearer between said access            node and said core network;    -   sending to said relay capable UE, a command for establishing at        least said UE-to-UE bearer.

Preferably, said command is also directed to the establishment of thesecond UE-to-access node bearer.

According to the presented method, the access node is able todistinguish between traffic associated with said relay capable UE viasaid Radio Access Bearer and traffic associated with said remote UE oversaid Remote Radio Access Bearer. That is, the traffic from the remote UEand the traffic from the relay capable UE are carried over differentconnections.

One of the advantages of the presented method for the access node isthat the access node is able to use conventional mobility managementprocedures for, e.g., performing handovers. Another advantage is thatthe Remote Radio Access Bearer may have its own encryption and securitycontext. For the remote UE, it will look like a conventional securitycontext. The telecommunication network may see two different securitycontexts, one for the remote UE and one for the relay capable UE.

Another advantage of the above is that the access node as well as thecore network have separate representations for the remote UE and therelay capable UE, respectively, as well as their state. This means thatthere is a separate connection for each of the UEs, i.e. the remote UEand the relay capable UE, to the telecommunication network. As such, therelaying is performed in such a way that the access node and the corenetwork are able to distinguish the traffic associated with the relaycapable UE from the traffic associated with the remote UE, and are ableto manage the connections thereof separately. This includes, forexample, standard mobility and session management procedures.

One of the advantages of the presented method for the core network isthat the core network can perform Quality-of-Service, QoS, control andcharging for each of the UE's separately.

According to the present disclosure, said remote UE is directly madevisible to the access node by introducing the second UE-to-access nodebearer, which is established between the relay capable UE and the accessnode. The relay capable UE may thus act as a relay of signalling anduser plane traffic between the remote UE and the radio access network,i.e. the access node.

It is noted that, typically, each of the nodes involved in theestablishing process may store information required to forward trafficin both directions. This information may, for example, be anidentification of the UE-to-UE bearer, the second UE-to-access nodebearer, the access node-to-core network bearer and/or an identificationof the remote UE and the relay capable UE.

The Remote Radio Access Bearer between the remote UE, i.e. the first endpoint, and the core network, i.e. the second end point, actuallycomprises three bearers associated to each other. These three bearersconstitute the UE-to-UE bearer established between the remote UE and therelay capable UE, the second UE-to-access node bearer establishedbetween the relay capable UE and the access node, and finally the accessnode-to-core network bearer established between the access node and thecore network. Identifications of these three bearers in relation to theRemote Radio Access Bearer may be stored in intermediate nodes in orderfor the intermediate nodes to be able to associate these three bearerswith the Remote Radio Access Bearer. For example, the relay capable UEmay store identifications of the UE-to-UE bearer as well as the secondUE-to-access node bearer. The access node may store identifications ofthe second UE-to-access node bearer as well as the access node-to-corenetwork bearer.

In an embodiment, the Request Relay message comprises an identifier foridentifying said remote UE at the access node, wherein said methodfurther comprises the steps of:

-   -   determining that said remote UE already has an established        non-relayed connection with said access node based on said        identifier, and    -   sending a command for releasing said established non-relayed        connection once an acknowledgement message has been received.

The above described embodiment is directed to the scenario that theremote UE, initially, has a direct, i.e. non-relayed connection to thecore network. That is, the remote UE may be connected to the corenetwork in a conventional manner by, for example, an established RadioAccess Bearer between itself and the core network.

After a while, the remote UE may decide that it would be beneficial tohave a relayed connection to the core network. Such a decision may, forexample, be based on a non-reliable non-relayed connection, or thedesire to save battery power by using a nearby device as relay. As such,using a relayed connection, the remote UE may be connected to the corenetwork in a more stable, reliable and more battery power efficientmanner.

In order to discover a relay capable UE, the remote UE may perform aProSe discovery method as described in, for example, TS 23.303, chapter5.3 ProSe Direct Discovery. The result of such a discovery method isfinding a relay capable UE that may act as a relay for the remote UEtowards the telecommunication network.

In accordance with the above described embodiment, the same access nodeis used for both the connection of the relay capable UE to the networkand the direct, i.e. non-relayed, connection of the remote UE to thenetwork. As such, it is preferred that a non-relayed connection to thecore network of the remote UE is already established via that sameaccess node. To determine whether the non-relayed connection of theremote UE to the core network is established via the access node, anidentifier may be provided in the Request Relay message for identifyingthe remote UE at the access node. The identifier is, for example, a CellRadio Network Temporary Identifier, or other similar identifier thatidentifies the UE at the access node. The access node may thus be ableto determine whether it already has a connection to the remote UE usingthe identifier in the Request Relay message.

Finally, once the bearers for the Remote Radio Access Bearer have beenestablished between the remote UE and the relay capable UE, between therelay capable UE and the access node, and between the access node andthe core network, the non-relayed connection between the remote UE andthe core network may be released, i.e. the underlying bearers for theRAB may be released. This action may be performed upon receipt of anacknowledgement message from the relay capable UE indicating that therequested bearers between the remote UE and the relay capable UE andbetween the relay capable UE and the access node are established and/orupon receipt of an acknowledgement message from the core network that anew access node to core network node bearer has been established, orupon receipt of both acknowledgement messages. It might also be possiblethat one of the bearers of the RAB is re-used and not released.

Following the above, initially, a Radio Access Bearer was establishedbetween the remote UE and the core network. This Radio Access Bearercomprised a UE-to-access node bearer and an access node-to-core networkbearer. This Radio Access Bearer becomes the Remote Radio Access Beareronce the decision has been made, for example by the remote UE, to startrelaying via the relay capable UE. In this particular case a newUE-to-UE bearer, i.e. between the remote UE and the relay capable UE maybe added to the already existing Radio Access Bearer, and a newUE-to-access node bearer, i.e. between the relay capable UE and theaccess node, may be established. These different bearers may all beassociated with the Remote Radio Access Bearer that does not change itsidentification. The core network does not necessarily need to know thatanything has changed, it may still see the same Radio Access Bearer. So,the nodes in the core network would not necessarily see the differencebetween the original Radio Access Bearer and the Remote Radio AccessBearer.

The above described embodiment is, for example, an embodiment directedto a remote UE being in EPS Connection Management, ECM, connected mode.

In a further embodiment, the step of receiving the Request Relay messagefurther comprises:

-   -   receiving from said relay capable UE initiated by said remote        UE, a service request message for requesting services from said        telecommunication network,    -   forwarding said service request message to a Mobility Management        network function, comprised by said telecommunication network,    -   receiving from said Mobility Management network function, an        accept message indicating approval for said requested services        by said remote UE.

This above described embodiment is directed, for example, to thesituation in which the remote UE is in ECM-idle mode. In this particularcase, a service request, for example a Non-Access Stratum, NAS, servicerequest, is received for requesting services from the telecommunicationnetwork. The request is forwarded to a Mobility Management networkfunction, for example a Mobility Management Entity, MME, comprised bythe telecommunication network. Typically, a Mobility Management Entitysends an initial Context Setup Request to the access node in reply tothe received service request.

The advantage of the above described embodiment is that the remote UEcan be connected to the telecommunication network via the relay capableUE, even in the situation when the remote UE does not have a separate,non-relayed connection established to the telecommunication network.From the perspective of the core network, the remote UE may be connectedin the same way as a UE that is connected directly, i.e. non-relayed.

In a further embodiment, the method comprises the step of:

-   -   receiving an acknowledgement message, from said relay capable        UE, wherein said acknowledgement message comprises an indication        that said UE-to-UE bearer has been established.

Preferably, said acknowledgement message comprises an indication thatsaid second UE-to-access node bearer has also been established.

The advantage of this embodiment is that the access node is made awareof the fact that the UE-to-UE bearer and the second UE-to-access nodebearer have been established.

In yet another embodiment, the access node is a base station in acellular network, for example an evolved node B, eNB.

The expressions, i.e. the wording, of the different aspects comprised bythe method and devices according to the present disclosure should not betaken literally. The wording of the aspects is merely chosen toaccurately express the rationale behind the actual functioning of theaspects.

In accordance with the present disclosure, different aspects applicableto the above mentioned examples of the methods in a first aspect of theinvention, including the advantages thereof, correspond to the aspectswhich are applicable to methods of the second aspect or the third aspectof the invention.

In a second aspect of the invention, there is provided a method ofestablishing a connection between a remote User Equipment, UE, and atelecommunication network via a relay capable UE, wherein saidtelecommunication network comprises a core network and an accessnetwork, said access network comprising an access node, wherein saidrelay capable UE has an established Radio Access Bearer between saidrelay capable UE and said core network, wherein said established RadioAccess Bearer comprises:

-   -   a first UE-to-access node bearer between said relay capable UE        and said access node;    -   an access node-to-core network bearer between said access node        and said core network;    -   said method comprising the steps of:    -   receiving a Request Relay message, from said remote UE, wherein        said Request Relay message comprises a request, from said remote        UE, for using said relay capable UE as a relay to the core        network, wherein said request is associated with establishment        of a Remote Radio Access Bearer, wherein said Remote Radio        Access Bearer comprises:        -   a UE-to-UE bearer between said remote UE and said relay            capable UE;        -   a second UE-to-access node bearer between said relay capable            UE and said access node, wherein said second UE-to-access            node bearer is different from said first UE-to-access node            bearer, and        -   an access node-to-core network bearer between said access            node and said core network;    -   sending said Request Relay message to said access node, and    -   receiving from said access node, a command for establishing at        least said UE-to-UE bearer.

Preferably, said command is also directed to the establishment of thesecond UE-to-access node bearer.

In an embodiment, the method further comprises the step of:

-   -   sending an acknowledgement message, to said access node wherein        said acknowledgement message comprises an indication that said        UE-to-UE bearer has been established.

Preferably, said acknowledgement message comprises an indication thatsaid second access node-to-core network bearer has also beenestablished.

In a third aspect, the invention provides for a method of establishing aconnection between a remote User Equipment, UE, and a telecommunicationnetwork via a relay capable UE, wherein said telecommunication networkcomprises a core network and an access network, said access networkcomprising an access node, wherein said relay capable UE has anestablished Radio Access Bearer between said relay capable UE and saidcore network, wherein said established Radio Access Bearer comprises:

-   -   a first UE-to-access node bearer between said relay capable UE        and said access node, and    -   an access node-to-core network bearer between said access node        and said core network;    -   said method comprising the steps of:    -   sending to said relay capable UE, a Request Relay message,        wherein said Request Relay message comprises a request for using        said relay capable UE as a relay to the core network, wherein        said request is associated with establishment of a Remote Radio        Access Bearer, wherein said Remote Radio Access Bearer        comprises:        -   a UE-to-UE bearer between said remote UE and said relay            capable UE;        -   a second UE-to-access node bearer between said relay capable            UE and said access node, wherein said second UE-to-access            node bearer is different from said first UE-to-access node            bearer, and        -   an access node-to-core network bearer between said access            node and said core network;    -   establishing a corresponding UE-to-UE signalling connection, and    -   transporting Non-Access Stratum, NAS, signalling between said        remote UE and said core network over said UE-to-UE signalling        connection.

In an embodiment, the method further comprises the steps of:

-   -   receiving a command for releasing a direct, non-relayed        connection between said remote UE and said telecommunication        network via said access node, and    -   releasing said direct, non-relayed connection in response to        said received command.

In another embodiment, the method further comprises the step of:

-   -   performing a discovery process for discovering UE's in a        proximity of said remote UE, wherein said relay capable UE is        one of said discovered UE's.

In a fourth aspect, the invention provides for a non-transitorycomputer-readable storage medium, comprising instructions which, whenexecuted on at least one processor, cause the at least one processor tocarry out the method according to any of the embodiments as describedabove.

Any type of computer readable storage medium may be utilized. Thecomputer readable storage medium may be, for example, but not limitedto, an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory, RAM, a read-only memory, ROM, an erasableprogrammable read-only memory, a portable compact disc read-only memory,an optical storage device, a magnetic storage device, or any suitablecombination of the foregoing.

In a fifth aspect, the invention provides for an access node arrangedfor establishing a connection between a remote User Equipment, UE, and atelecommunication network via a relay capable UE, wherein saidtelecommunication network comprises a core network and an accessnetwork, said access network comprising an access node, wherein saidrelay capable UE has an established Radio Access Bearer between saidrelay capable UE and said core network wherein said established RadioAccess Bearer comprises:

-   -   a first UE-to-access node bearer between said relay capable UE        and said access node, and    -   an access node-to-core network bearer between said access node        and said core network;    -   said access node comprising:    -   a receiver arranged for receiving a Request Relay message, from        said relay capable UE, wherein said Request Relay message        comprises a request, originating from said remote UE, for using        said relay capable UE as a relay to the core network, wherein        said request is associated with establishment of a Remote Radio        Access Bearer, wherein said Remote Radio Access Bearer        comprises:        -   a UE-to-UE bearer between said remote UE and said relay            capable UE;        -   a second UE-to-access node bearer between said relay capable            UE and said access node, wherein said second UE-to-access            node bearer is different from said first UE-to-access node            bearer, and        -   an access node-to-core network bearer between said access            node and said core network;    -   a transmitter arranged for sending to said relay capable UE, a        command for establishing at least said UE-to-UE bearer.

In a sixth aspect, the invention provides for a relay capable UserEquipment, UE, arranged for establishing a connection between a remoteUser Equipment, UE, and a telecommunication network via a relay capableUE, wherein said telecommunication network comprises a core network andan access network, said access network comprising an access node,wherein said relay capable UE has an established Radio Access Bearerbetween said relay capable UE and said core network, wherein saidestablished Radio Access Bearer comprises:

-   -   a first UE-to-access node bearer between said relay capable UE        and said access node;    -   an access node-to-core network bearer between said access node        and said core network;    -   said relay capable UE comprising:    -   a receiver arranged for receiving a Request Relay message, from        said remote UE, wherein said Request Relay message comprises a        request for using said relay capable UE as a relay to the core        network, wherein said request is associated with establishment        of a Remote Radio Access Bearer, wherein said Remote Radio        Access Bearer comprises:        -   a UE-to-UE bearer between said remote UE and said relay            capable UE;        -   a second UE-to-access node bearer between said relay capable            UE and said access node, wherein said second UE-to-access            node bearer is different from said first UE-to-access node            bearer, and        -   an access node-to-core network bearer between said access            node and said core network;    -   a transmitter arranged for sending said Request Relay message to        said access node, and    -   wherein said receiver is further arranged for receiving from        said access node, a command for establishing at least said        UE-to-UE bearer.

In a seventh aspect, there is provided a remote User Equipment, UE,arranged for establishing a connection between a remote User Equipment,UE, and a telecommunication network via a relay capable UE, wherein saidtelecommunication network comprises a core network and an accessnetwork, said access network comprising an access node, wherein saidrelay capable UE has an established Radio Access Bearer between saidrelay capable UE and said core network, wherein said established RadioAccess Bearer comprises:

-   -   a first UE-to-access node bearer between said relay capable UE        and said access node, and    -   an access node-to-core network bearer between said access node        and said core network;    -   said remote UE comprising:    -   a transmitter arranged for sending to said relay capable UE, a        Request Relay message, wherein said Request Relay message        comprises a request for using said relay capable UE as a relay        to the core network, wherein said request is associated with        establishment of a Remote Radio Access Bearer, wherein said        Remote Radio Access Bearer comprises:        -   a UE-to-UE bearer between said remote UE and said relay            capable UE;        -   a second UE-to-access node bearer between said relay capable            UE and said access node, wherein said second UE-to-access            node bearer is different from said first UE-to-access node            bearer, and        -   an access node-to-core network bearer between said access            node and said core network;    -   a processor arranged for establishing a corresponding UE-to-UE        signalling connection and for transporting Non-Access Stratum,        NAS, signalling between said remote UE and said core network        over said UE-to-UE signalling connection.

The advantage of having a Non-Access Stratum, NAS, signalling connectionis that via the NAS signalling connection, the remote UE can send anysignalling messages to any core network node, e.g. an MobilityManagement Entity, MME, that a directly connected UE would also be ableto send. This reduces the impact of relaying on the behaviour of theremote UE in order to deal with relaying.

The above-mentioned and other features and advantages of the disclosurewill be best understood from the following description referring to theattached drawings. In the drawings, like reference numerals denoteidentical parts or parts performing an identical or comparable functionor operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an established Remote Radio Access Bearer between theremote UE and the core network of the telecommunication network.

FIG. 2 shows a signalling diagram in which a UE-to-UE bearer as well asa second UE-to-access node bearer is established for a remote UE inconnected mode.

FIG. 3 shows a signalling diagram in which a UE-to-UE bearer as well asa second UE-to-access node bearer is established for a remote UE in idlemode.

FIG. 4 shows a signalling diagram in which the relaying for the remoteUE is stopped.

FIG. 5 shows a signalling diagram in which the remote UE switches froman idle mode to a connected mode during relaying by the relay capableUE.

FIG. 6 shows an example of a control plane stack between the remote UE,the relay capable UE, the access node as well as the core network.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic illustration 1 of an established Remote RadioAccess Bearer 6 between the remote User Equipment, UE, 2 and the corenetwork as indicated with reference numeral 5. In a more specificexample, e.g. in an LTE network, the Remote Radio Access Bearer 6 isestablished between the remote UE 2 and any of a Mobility ManagementFunction, such as a Mobility Management Entity, MME, or a gatewayfunction, such as the serving gateway, SGW.

The core network 5 could be the Evolved Packet Core, EPC. In such acase, the SGW anchors user-plane mobility in a SGW serving area andfunctions as a termination point of the packet data network interfacetowards the access network, i.e. the access node 4. The MME is involvedin the bearer activation and deactivation process and is responsible forchoosing the SGW for the remote UE 2 at the initial attach thereof tothe network. Further, the MME is responsible for authenticating theremote UE 2, for example by interacting with the Home Subscriber Server,HSS. The Non Access Stratum, NAS, signalling terminates at the MME andit is also responsible for generation and allocation of temporaryidentities to UE's.

The schematic illustration 1 of FIG. 1 shows that the Remote RadioAccess Bearer 6 is established via the relay capable UE 3 and the accessnode 4. The access node 4 is, for example, a base station in a cellularnetwork. More specifically, the access node 4 may be an Evolved Node B,eNB in an LTE network or a NodeB in an UMTS network. In case of acentralized Radio Access Network an access node 4 may be a combinationof a radio function unit, referred to as Remote Radio Head, and aprocessor function, referred to as the Base Band Unit. Other splits offunctionality of an access node may also be possible.

The Remote Radio Access Bearer 6 is considered a logical bearerestablished between the remote UE 2 and the core network 5. The RemoteRadio Access Bearer 6 actually comprises three separate bearers.

A first of these three bearers is indicated with reference numeral 7.This bearer is a UE-to-UE bearer 7 and is established between the remoteUE 2 and the relay capable UE 3. Such a bearer is thus established tosupport device to device communication, or ProSe communication. In the3GPP architecture for LTE, the UE-to-UE bearer 7 would be considered tobe established over the PC5 interface.

A second of these three bearers is indicated with reference numeral 8and is referenced to as the second UE-to-access node bearer 8. Thisbearer may be a radio bearer 8 and is established between the relaycapable UE 3 and the access node 4. This radio bearer 8 is intended tocarry traffic to, and from, the remote UE 2 only. In the 3GPParchitecture for LTE, the UE-to-access node bearer 8 would be consideredto be established over the Uu interface.

A third of these three bearers is indicated with reference numeral 9 andis referenced to as an access node-to-core network bearer 9. This beareris established between the access node 4 and the core network 5. In the3GPP architecture for LTE, the access node-to-core network bearer 9would be considered to be established over the S1 interface.

It is noted that for the ProSe communication, two different scenario'smay exist, i.e. an “in coverage” scenario and a “partial coverage”scenario. In an “in coverage” scenario, the remote UE 2 as well as therelay capable UE 3 are within coverage range of the access node 4, andthe network may control the resources used for ProSe communication.

In a partial coverage situation such a centralized control may not befeasible. That is, the remote UE 2 is not in direct coverage of theaccess node 4 and the relay capable UE 3 is in direct coverage of theaccess node 4.

The schematic illustration 1 of FIG. 1 further shows an establishedRadio Access Bearer 10 between the relay capable UE 3 and the corenetwork 5. This specific Radio Access Bearer 10 is a dedicated bearerfor the relay capable UE 3. As such, this bearer is not used forcommunication to, and from, the remote UE 2. The Radio Access Bearer 10comprises two separate bearers which are associated to the Radio AccessBearer 10.

The first bearer is referenced to as a first UE-to-access node bearer 11and is established between the relay capable UE 3 and the access node 4.The second bearer is referenced to as an access node-to-core networkbearer 12 and is established between the access node 4 and the corenetwork 5.

It is noted that the solution of introducing a Remote Radio AccessBearer 6 makes the remote UE 2 directly visible to the access network 4and core network 5, while the remote UE 2 is being relayed via the relaycapable UE 3. The relay capable UE 3 will then act as a relay ofsignalling and user plane traffic between the remote UE 2 and the accessnode 4.

The Remote Radio Access Bearer 6 represents the connection of the remoteUE 2 to the core network 5 and may be used for data transfer. Each ofthe nodes over which the Remote Radio Access Bearer 6 is established maystore information required to forward the traffic in both directions.This type of information may be the bearer or connection identificationsused to create associations which a node accesses to find where toforward packets belonging to the Remote Radio Access Bearer 6. Theseassociations may be saved during the establishment of the Remote RadioAccess Bearer 6.

Following the above, the access node 4 is thus able to distinguishbetween traffic with said relay capable UE 3 over said firstUE-to-access node bearer 11 and traffic with said remote UE over saidsecond UE-to-access node bearer 8.

FIG. 2 shows a signalling diagram 101 in which a UE-to-UE bearer as wellas a second UE-to-access node bearer is established for a remote UE inconnected mode.

Here below, an explanation of the signalling diagram 101 is providedwith references to the ECM-Connected state as known in the Long TermEvolution, LTE, network. A similar, or the same, state is however alsoknown in other networks, making the signalling diagram 101 alsoapplicable to these types of networks.

In the signalling diagram 101, the remote UE is indicated with referencenumeral 102, the relay capable UE is indicated with reference numeral103, the access node is indicated with reference numeral 104, the corenetwork is indicated with reference numeral 105 and the ProSe Functionis indicated with reference numeral 106.

Here, reference numeral 107 indicates that the remote UE 102 has alreadyattached a non-relayed, direct connection to the core network 105. Assuch, the remote UE 102 is within the coverage area of the access node104. The remote UE 102 has thus connected to the network in a standard,conventional manner.

The remote UE 102 may decide that it would like a relayed connectiontowards the network. In order to discover potential UEs that could serveas a relay for the remote UE 102, the remote UE 102 may initiate aproximity-based applications and services, ProSe, discovery process 108.

A ProSe discovery process 108 is a process that identifies a UE that isProSe-enabled in the proximity of another, using evolved UMTSTerrestrial Radio Access, E-UTRA or the evolved packet core, EPC. Thedepicted ProSe discovery process 108 may result in the discovery of therelay capable UE 103, i.e. a UE that is capable to act as a relay forthe remote UE 102.

Following the discovery of the relay capable UE 103, the remote UE 102sends 109 a Request Relay message to the discovered relay capable UE 103via a PC5 connection. The message is a request from the remote UE 102for using the relay capable UE 103 as a relay to the core network 105.This Request Relay message may include an identifier, for example thetemporary Cell Radio Network Temporary Identifier, C-RNTI, foridentifying said remote UE 102 at the access node 104. The message mayfurther comprise information with respect to Quality-of-Service, QoS,requirements that the remote UE 102 needs or already has on existingRadio Bearers.

The relay capable UE 103 may perform checks 110, i.e. processingconstraints, QoS parameters, allowed UE's to be relayed, etc., whetherto authorize the relaying of the remote UE 102. In case of a positiveoutcome, the relay capable UE 103 sends 111 the Request Relay messagetowards the access node 104. In another embodiment, the relay capable UE103 sends 111 the Request Relay message towards the access node 104without performing checks 110.

The access node 104 will then find, if available, the connection 107 italready has to the remote UE 102 based on the identifier, i.e. thetemporary Cell Radio Network Temporary Identifier, present in theRequest Relay message. If it is determined 112 that the initialconnection 107 of the remote UE 102 to the core network 105 is notestablished via the same access node 104 as the connection of the relaycapable UE 103 to the core network 105, a Request Relay Complete messageis sent 124, 125 from the access node 104, via the relay capable UE 103to the remote UE 102. This message indicates that relay is currently notpossible. An alternative to sending the Request Relay Complete messageis to perform a handover such that the remote UE is serviced by the sameaccess node as the relay capable UE. The block indicated with referencenumeral 126 depicts the situation that the remote UE 102 is to releaseits connection 107 to the core network 105, and is to initiate the startof the relaying process from the ECM-Idle state as will be elucidatedwith respect to FIG. 3.

On the determination that the initial connection 107 of the remote UE102 to the core network 105 is established via the same access node 104as the connection of the relay capable UE 103 to the core network 105,the access node 104 sends 113 a command for establishing the UE-to-UEbearer and the second UE-to-access node bearer. This command is, forexample, coupled to an RRC Radio Bearer Setup procedure message havingembedded therein an PC5 bearer setup flag.

The relay capable UE 103 receives the command and uses, for example, PC5signalling 114 to invoke a UE-to-UE bearer setup between the remote UE102 and the relay capable UE 103, for example the PC5 bearer setup.

When the relay capable UE 103 has received 115 a confirmation to the PC5bearer setup from the remote UE 102, and the second UE-to-access nodebearer has been established between the relay capable UE 103 and theaccess node, the relay capable UE 103 may acknowledge 117 theestablishment of both bearers to the access node 104. The relay capableUE 103 may further save 116 any information necessary to relay PacketData Convergence Protocol, PDCP, data between the remote UE 102 and theaccess node 104.

Once the UE-to-UE bearer has been established and once the secondUE-to-access node bearer has been established, the access node 104 maystore 118 the information related to the underlying bearers of theRemote Radio Access Bearer, i.e. the established UE-to-UE bearer, theestablished UE-to-access node bearer and an access node-to-core networkbearer. The access node-to-core network bearer may be the same bearer aswas previously used for the connection of the remote UE to the networkor it may also be a different bearer. Typically, such a bearer is the S1bearer.

Finally, the access node 104 sends 120 a Request Relay Complete messageto the relay capable UE 103, which, in turn, sends 121 this message tothe remote UE 102 indicating that the Remote Radio Access Bearer hasbeen established. Further, the access node 104 may send a command 122 tothe remote UE 102 to release its initial connection 107 to the corenetwork. Alternatively, the access node 104 could release the connection107 by itself and acknowledge this to the remote UE. The procedure isthen completed by the remote UE 102 updating its tracking area 123 tothe core network 105, using a Non Access Stratum, NAS, connection.

FIG. 3 shows a signalling diagram 201 in which a UE-to-UE bearer as wellas a second UE-to-access node bearer is established for a remote UE inidle mode. In this respect, the remote UE is indicated with referencenumeral 202, the relay capable UE is indicated with reference numeral203, the access node is indicated with reference numeral 204, the corenetwork is indicated with reference numeral 205 and the ProSe functionis indicated with reference numeral 206.

The signalling diagram 201 depicted in FIG. 3 discloses the situation inwhich the remote UE 202 does not have a Radio Access Bearer establishedto the core network 205, or in the situation that the remote UE 202 haslost its connection, but is still known in the network. In these kindsof situations, the procedure is supplemented with an additional servicerequest message which will be explained in more detail here below.

In a first step, the remote UE 202 attaches 207 to the core network 205in a conventional manner. Second, the remote UE 202 performs a ProSediscovery process 208 to determine whether there are UE's in itsproximity that could serve as a relay for a connection to the corenetwork 205. These two steps are also explained with reference to FIG. 2and will not be explained here in more detail.

Different from the scenario in FIG. 2 is that here, the remote UE is inidle mode 209, which is for example indicated with the ECM-IDLE state ina Long Term Evolution, LTE, network.

Again, the remote UE 202 sends 210 a Request Relay message towards therelay capable UE 203 for using the relay capable UE 203 as a relay tothe core network 205. Here, the Request Relay message also comprises aService Request for requesting services from the telecommunicationnetwork. The service request may, alternatively, also be sent in aseparate message. Such a service request is, for example, an LTE ServiceRequest message directed to the MME.

The relay capable UE 203 then may again perform checks 211 to determinewhether it can serve as a relay for the remote UE 202, and, if approved,it forwards 212 the Request Relay message, comprising the servicerequest, to the access node 204. In an alternative embodiment, the relaycapable UE 203 sends 212 the Request Relay message towards the accessnode 204 without performing checks 211.

Upon receipt of the Request Relay message, the access node 204 forwards213 the service request to the core network 205, and receives 214 acontext setup procedure from the core network 205, for example from theMobility Management Entity.

Most of the remainder steps depicted in FIG. 3 are the same, or similarto the steps depicted in FIG. 2 and are therefore not explained indetail. That is, step 215 corresponds to step 113, step 216 correspondsto step 114, step 217 corresponds to step 115, step 218 corresponds tostep 116, step 219 corresponds to step 117, step 220 corresponds to 118,step 222 corresponds to step 120, step 223 corresponds to step 121 andstep 224 corresponds to step 123. In addition to the above, the accessnode 204 confirms 221 to the core network 205 that the context setupprocedure is completed.

FIG. 4 shows a signalling diagram 301 in which the relaying for theremote UE is stopped.

Here, the remote UE is indicated with reference numeral 302, the relaycapable UE is indicated with reference numeral 303, the access node isindicated with reference numeral 304 and the core network is indicatedwith reference numeral 305.

In this situation a Remote Radio Access Bearer 306 is establishedbetween the remote UE 302 and the core network 305 via the relay capableUE 303 and the access node 304.

The remote UE 302 decides to cancel the relaying of traffic via therelay capable UE 303 (e.g. because the remote UE 302 notices that theconnection with the relay capable UE 303 is deteriorating) and sends 307a Request Relay Cancel message to the access node 304 via, for example,Access Stratum signalling.

The access node 304 is able to determine 308 that the connection fromthe remote UE 302 is being relayed via the relay capable UE 303 using anidentification of the remote UE 302 or a direct identification of theUE-to-UE bearer established between the remote UE 302 and the relaycapable UE 303. Alternatively, the Request Relay Cancel message sent 307comprises an identification of the Remote Radio Access Bearer for whichrelaying needs to be cancelled. In this case, the access node 304 mayhave the context information stored to determine that this particularRadio Access Bearer is in fact a Remote Radio Access Bearer. A RadioBearer Setup message is then sent 309 by the access node 304 to theremote UE 302 to initiate the establishment of a radio bearer directlybetween the remote UE 302 and the access node 304. This new radio beareris not to be established via the relay capable UE 303.

The remote UE 302 then confirms 310 the establishment of the RadioBearer, and the remote UE 302 starts using 311 the bearer for, forexample, uplink data. Then, the access node 304 confirms 312 cancellingof the relay, changes 313 the specific Remote Radio Access Bearer into anormal Radio Access Bearer 306 and starts using 314 the direct radiobearer to the remote UE 302 for downlink traffic.

Upon completion of the relay cancelling, the access node 304 orders therelay capable UE 303 to release all relay resources by sending 315, 316a Radio Bearer Release message comprising a UE-to-UE bearer releaseFlag. This triggers the release procedure to the remote UE 302, and isacknowledged, by the remote UE 302, in an acknowledgement message 317,318 towards the access node 304.

If in an alternative case the UE-to-UE connection is broken, a timeoutmechanism may be used to release the resources in the remote UE.

Finally, the access node removes 319 all information with respect to therelaying connection of the remote UE 302 to the core network 304 and theremote UE 302 updates 320 its tracking area to the core network 304.

FIG. 5 shows a signalling diagram 401 in which the remote UE switchesfrom an idle mode to a connected mode during relaying by the relaycapable UE.

Here, the remote UE is indicated with reference numeral 402, the relaycapable UE is indicated with reference numeral 403, the access node isindicated with reference numeral 404 and the core network is indicatedwith reference numeral 405.

In this situation, the remote UE 402 may use the relay capable UE 403 asa relay and its connectivity states are the same as when its connectionto the network is direct, i.e. not relayed. Moving from an idle state toa connected state may then be performed as shown in FIG. 5. That is, aservice request message, for example an NAS service request message, issent 406 over the UE-to-UE signalling connection to the relay capable UE403, which relay capable UE 403, in turn, forwards 407 that request tothe access node 404, which access node 404, in turn, forwards 408 therequest to the core network 405.

A confirmation is sent 409, 410, 411 by the core network 405 and isforwarded by each of the intermediate nodes 404, 403 to the remote UE402, wherein the confirmation comprises an UE-to-UE bearer setup flagfor indicating that the UE-to-UE bearer should be established.

The remote UE 402 then sends 412 a confirmation to the relay capable UE403 that the UE-to-UE bearer is established, and the relay capable UE403 stores 413 any information related to the relayed connection. Anidentification of the UE-to-UE bearer is then sent 414 to the accessnode, and the access node saves 415 any information, i.e. informationrelated to the Remote Radio Access Bearer, with respect to the remote UE402 as a relayed connection from the remote UE 402 to the core network405 via the relay capable UE 403. Finally, a confirmation is sent 416 tothe core network for indicating that the bearers have been established.

FIG. 6 shows an example of a control plane stack 501 between the remoteUE, the relay capable UE, the access node as well as the core network.

Here, the remote UE is indicated with reference numeral 502, the relaycapable UE is indicated with reference numeral 503, the access node isindicated with reference numeral 504 and the core network, morespecifically the MME, is indicated with reference numeral 505.

In this respect it is noted that the remote UE 502 is arranged forestablishing a connection between a remote UE and a telecommunicationnetwork via the relay capable UE 503. The remote UE comprises atransmitter arranged for sending to the relay capable UE 503, a RequestRelay message, wherein the Request Relay message comprises a request forusing the relay capable UE 503 as a relay to the core network.

The request is associated with establishment of a Remote Radio AccessBearer, wherein said Remote Radio Access Bearer comprises a UE-to-UEbearer between said remote UE and said relay capable UE, a secondUE-to-access node bearer between said relay capable UE and said accessnode, wherein said second UE-to-access node bearer is different fromsaid first UE-to-access node bearer, and an access node-to-core networkbearer between said access node and said core network.

The remote UE 502 further comprises a processor arranged forestablishing said UE-to-UE signalling connection, and for establishing aNon-Access Stratum, NAS, connection 506 between said remote UE and saidcore network over said established UE-to-UE signalling connection.Preferably, the NAS connection 506 is established over the PC5signalling connection.

Other variations to the disclosed embodiments can be understood andeffected by those skilled in the art in practicing the claimedinvention, from a study of the drawings, the disclosure, and theappended claims. In the claims, the word “comprising” does not excludeother elements or steps, and the indefinite article “a” or “an” does notexclude a plurality. A single processor or other unit may fulfil thefunctions of several items recited in the claims. The mere fact thatcertain measures are recited in mutually different dependent claims doesnot indicate that a combination of these measured cannot be used toadvantage. A computer program may be stored/distributed on a suitablemedium, such as an optical storage medium or a solid-state mediumsupplied together with or as part of other hardware, but may also bedistributed in other forms, such as via the Internet or other wired orwireless telecommunication systems. Any reference signs in the claimsshould not be construed as limiting the scope thereof.

1. A method of establishing a connection between a remote UserEquipment, UE, and a telecommunication network via a relay capable UE,wherein the telecommunication network comprises a core network and anaccess network, the access network comprising an access node, whereinthe relay capable UE has an established Radio Access Bearer between therelay capable UE and the core network wherein the established RadioAccess Bearer comprises: a first UE-to-access node bearer between therelay capable UE and the access node, and an access node-to-core networkbearer between the access node and the core network; the methodcomprising: receiving a Request Relay message, from the relay capableUE, comprising a request, originating from the remote UE, for using therelay capable UE as a relay to the core network, wherein the request isassociated with establishment of a Remote Radio Access Bearer, whereinthe Remote Radio Access Bearer comprises: a UE-to-UE bearer between theremote UE and the relay capable UE; a second UE-to-access node bearerbetween the relay capable UE and the access node, wherein the secondUE-to-access node bearer is different from the first UE-to-access nodebearer, and an access node-to-core network bearer between the accessnode and the core network; and sending to the relay capable UE, acommand for establishing at least the UE-to-UE bearer.
 2. The methodaccording to claim 1, wherein sending the command comprises sending thecommand for establishing the second UE-to-access node bearer.
 3. Themethod according to claim 1, wherein the Request Relay message comprisesan identifier for identifying the remote UE at the access node, whereinthe method further comprises: determining that the remote UE already hasan established non-relayed connection with the access node based on theidentifier; and sending a command for releasing the establishednon-relayed connection once an acknowledgement message has beenreceived.
 4. The method according to claim 1, wherein receiving theRequest Relay message further comprises: receiving from the relaycapable UE initiated by the remote UE, a service request message forrequesting services from the telecommunication network, forwarding theservice request message to a Mobility Management network function,comprised by the telecommunication network and receiving from theMobility Management network function, an accept message indicatingapproval for the requested services by the remote UE.
 5. The methodaccording to claim 1, wherein the method further comprises: receiving anacknowledgement message, from the relay capable UE, wherein theacknowledgement message comprises an indication that the UE-to-UE bearerhas been established.
 6. A method of establishing a connection between aremote User Equipment, UE, and a telecommunication network via a relaycapable UE, wherein the telecommunication network comprises a corenetwork and an access network, the access network comprising an accessnode, wherein the relay capable UE has an established Radio AccessBearer between the relay capable UE and the core network, wherein theestablished Radio Access Bearer comprises: a first UE-to-access nodebearer between the relay capable UE and the access node; an accessnode-to-core network bearer between the access node and the corenetwork; the method comprising: receiving a Request Relay messagecomprising a request, from the remote UE, for using the relay capable UEas a relay to the core network, wherein the request is associated withestablishment of a Remote Radio Access Bearer, wherein the Remote RadioAccess Bearer comprises: a UE-to-UE bearer between the remote UE and therelay capable UE; a second UE-to-access node bearer between the relaycapable UE and the access node, wherein the second UE-to-access nodebearer is different from the first UE-to-access node bearer, and anaccess node-to-core network bearer between the access node and the corenetwork; sending the Request Relay message to the access node; andreceiving from the access node, a command for establishing at least theUE-to-UE bearer.
 7. The method according to claim 6, wherein receivingthe command further comprises receiving the command for establishing thesecond UE-to-access node bearer.
 8. The method according to claim 6,wherein the method further comprises: sending an acknowledgementmessage, to the access node wherein the acknowledgement messagecomprises an indication that the UE-to-UE bearer has been established.9. A method of establishing a connection between a remote UserEquipment, UE, and a telecommunication network via a relay capable UE,wherein the telecommunication network comprises a core network and anaccess network, the access network comprising an access node, whereinthe relay capable UE has an established Radio Access Bearer between therelay capable UE and the core network, wherein the established RadioAccess Bearer comprises: a first UE-to-access node bearer between therelay capable UE and the access node, and an access node-to-core networkbearer between the access node and the core network; the methodcomprising: sending to the relay capable UE, a Request Relay messagecomprising a request for using the relay capable UE as a relay to thecore network, wherein the request is associated with establishment of aRemote Radio Access Bearer, wherein the Remote Radio Access Bearercomprises: a UE-to-UE bearer between the remote UE and the relay capableUE; a second UE-to-access node bearer between the relay capable UE andthe access node, wherein the second UE-to-access node bearer isdifferent from the first UE-to-access node bearer, and an accessnode-to-core network bearer between the access node and the corenetwork; establishing a corresponding UE-to-UE signalling connection;and transporting Non-Access Stratum, NAS, signalling between the remoteUE and the core network over the UE-to-UE signalling connection.
 10. Themethod according to claim 9, wherein the method further comprises:receiving a command for releasing a direct, non-relayed connectionbetween the remote UE and the telecommunication network via the accessnode; and releasing the direct, non-relayed connection in response tothe received command.
 11. The method according to claim 9, wherein themethod further comprises: performing a discovery process for discoveringUE's in a proximity of the remote UE, wherein the relay capable UE isone of the discovered UE's.
 12. A non-transitory computer-readablestorage medium having instructions stored thereon for establishing aconnection between a remote User Equipment, UE, and a telecommunicationnetwork via a relay capable UE, wherein the telecommunication networkcomprises a core network and an access network, the access networkcomprising an access node, wherein the relay capable UE has anestablished Radio Access Bearer between the relay capable UE and thecore network wherein the established Radio Access Bearer comprises: afirst UE-to-access node bearer between the relay capable UE and theaccess node, and an access node-to-core network bearer between theaccess node and the core network; wherein the instructions, whenexecuted by one or more processors, cause the one or more processors tocarry out operations including: receiving a Request Relay message, fromthe relay capable UE, comprising a request, originating from the remoteUE, for using the relay capable UE as a relay to the core network,wherein the request is associated with establishment of a Remote RadioAccess Bearer, wherein the Remote Radio Access Bearer comprises: aUE-to-UE bearer between the remote UE and the relay capable UE; a secondUE-to-access node bearer between the relay capable UE and the accessnode, wherein the second UE-to-access node bearer is different from thefirst UE-to-access node bearer, and an access node-to-core networkbearer between the access node and said the core network; and sending tothe relay capable UE, a command for establishing at least the UE-to-UEbearer.
 13. Access node arranged for establishing a connection between aremote User Equipment, UE, and a telecommunication network via a relaycapable UE, wherein the telecommunication network comprises a corenetwork and an access network, the access network comprising an accessnode, wherein the relay capable UE has an established Radio AccessBearer between the relay capable UE and the core network, wherein theestablished Radio Access Bearer comprises: a first UE-to-access nodebearer between the relay capable UE and the access node, and an accessnode-to-core network bearer between the access node and the corenetwork; the access node comprising: a receiver arranged for receiving aRequest Relay message, from the relay capable UE, comprising a request,originating from the remote UE, for using the relay capable UE as arelay to the core network, wherein the request is associated withestablishment of a Remote Radio Access Bearer, wherein the Remote RadioAccess Bearer comprises: a UE-to-UE bearer between the remote UE and therelay capable UE; a second UE-to-access node bearer between the relaycapable UE and the access node, wherein the second UE-to-access nodebearer is different from the first UE-to-access node bearer, and anaccess node-to-core network bearer between the access node and the corenetwork; and a transmitter arranged for sending to the relay capable UE,a command for establishing at least the UE-to-UE bearer.
 14. Relaycapable User Equipment, UE, arranged for establishing a connectionbetween a remote User Equipment, UE, and a telecommunication network viaa relay capable UE, wherein the telecommunication network comprises acore network and an access network, the access network comprising anaccess node, wherein the relay capable UE has an established RadioAccess Bearer between the relay capable UE and the core network, whereinthe established Radio Access Bearer comprises: a first UE-to-access nodebearer between the relay capable UE and the access node; an accessnode-to-core network bearer between the access node and the corenetwork; the relay capable UE comprising: a receiver arranged forreceiving a Request Relay message, from the remote UE, wherein theRequest Relay message comprises a request for using the relay capable UEas a relay to the core network, wherein the request is associated withestablishment of a Remote Radio Access Bearer, wherein the Remote RadioAccess Bearer comprises: a UE-to-UE bearer between the remote UE and therelay capable UE; a second UE-to-access node bearer between the relaycapable UE and the access node, wherein the second UE-to-access nodebearer is different from the first UE-to-access node bearer, and anaccess node-to-core network bearer between the access node and the corenetwork; and a transmitter arranged for sending the Request Relaymessage to the access node, and wherein the receiver is further arrangedfor receiving from the access node, a command for establishing at leastthe UE-to-UE bearer.
 15. A remote User Equipment, UE, arranged forestablishing a connection between a remote User Equipment, UE, and atelecommunication network via a relay capable UE, wherein thetelecommunication network comprises a core network and an accessnetwork, the access network comprising an access node, wherein the relaycapable UE has an established Radio Access Bearer between the relaycapable UE and the core network, wherein the established Radio AccessBearer comprises: a first UE-to-access node bearer between the relaycapable UE and the access node, and an access node-to-core networkbearer between the access node and the core network; the remote UEcomprising: a transmitter arranged for sending to the relay capable UE,a Request Relay message comprising a request for using the relay capableUE as a relay to the core network, wherein the request is associatedwith establishment of a Remote Radio Access Bearer, wherein the RemoteRadio Access Bearer comprises: a UE-to-UE bearer between the remote UEand the relay capable UE; a second UE-to-access node bearer between therelay capable UE and the access node, wherein the second UE-to-accessnode bearer is different from the first UE-to-access node bearer, and anaccess node-to-core network bearer between the access node and the corenetwork; and a processor arranged for establishing a correspondingUE-to-UE signalling connection, and for transporting Non-Access Stratum,NAS, signalling between the remote UE and the core network over theUE-to-UE signalling connection.
 16. A non-transitory computer-readablestorage medium having instructions stored thereon for establishing aconnection between a remote User Equipment, UE, and a telecommunicationnetwork via a relay capable UE, wherein the telecommunication networkcomprises a core network and an access network, the access networkcomprising an access node, wherein the relay capable UE has anestablished Radio Access Bearer between the relay capable UE and thecore network, wherein the established Radio Access Bearer comprises: afirst UE-to-access node bearer between the relay capable UE and theaccess node; an access node-to-core network bearer between the accessnode and the core network; wherein the instructions, when executed byone or more processors, cause the one or more processors to carry outoperations including: receiving a Request Relay message comprising arequest, from the remote UE, for using the relay capable UE as a relayto the core network, wherein the request is associated withestablishment of a Remote Radio Access Bearer, wherein the Remote RadioAccess Bearer comprises: a UE-to-UE bearer between the remote UE and therelay capable UE; a second UE-to-access node bearer between the relaycapable UE and the access node, wherein the second UE-to-access nodebearer is different from the first UE-to-access node bearer, and anaccess node-to-core network bearer between the access node and the corenetwork; sending the Request Relay message to the access node; andreceiving from the access node, a command for establishing at least theUE-to-UE bearer.
 17. A non-transitory computer-readable storage mediumhaving instructions stored thereon for establishing a connection betweena remote User Equipment, UE, and a telecommunication network via a relaycapable UE, wherein the telecommunication network comprises a corenetwork and an access network, the access network comprising an accessnode, wherein the relay capable UE has an established Radio AccessBearer between the relay capable UE and the core network, wherein theestablished Radio Access Bearer comprises: a first UE-to-access nodebearer between the relay capable UE and the access node, and an accessnode-to-core network bearer between the access node and the corenetwork; the method comprising: sending to the relay capable UE, aRequest Relay message comprising a request for using the relay capableUE as a relay to the core network, wherein the request is associatedwith establishment of a Remote Radio Access Bearer, wherein the RemoteRadio Access Bearer comprises: a UE-to-UE bearer between the remote UEand the relay capable UE; a second UE-to-access node bearer between therelay capable UE and the access node, wherein the second UE-to-accessnode bearer is different from the first UE-to-access node bearer, and anaccess node-to-core network bearer between the access node and the corenetwork; establishing a corresponding UE-to-UE signalling connection;and transporting Non-Access Stratum, NAS, signalling between the remoteUE and the core network over the UE-to-UE signalling connection.